Patents by Inventor William Alan Stewart Butement

William Alan Stewart Butement has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Electro-photographic element
    Patent number: 4060321
    Abstract: An electro-photographic apparatus in which the photo-conductive material is on an optically transparent base, the voltage at each position on the photo-conductive material or on small areas of conductive material associated therewith being dependent on the amount of light impinging on the photo-conductive layer through the transparent base and on a potential set up between an electrically conductive layer located between the base and the photo-conductive layer and on an element located on the other side of the photo-conductive layer, pigment being accepted in an amount depending on the variable voltage.
    Type: Grant
    Filed: January 14, 1976
    Date of Patent: November 29, 1977
    Inventor: William Alan Stewart Butement
  • Electro-photographic method and element
    Patent number: 3941593
    Abstract: An electro-photographic method and apparatus in which the photo-conductive material is on an optically transparent base, the voltage at each position on the photo-conductive material or on small areas of conductive material associated therewith being depended on the amount of light impinging on the photo-conductive layer through the transparent base and on a potential set up between an electrically conductive layer located between the base and the photo-conductive layer and on an element located on the other side of the photo-conductive layer, pigment being accepted in an amount depending on the variable voltage.
    Type: Grant
    Filed: November 22, 1972
    Date of Patent: March 2, 1976
    Inventor: William Alan Stewart Butement